I mean, Josie isn't necessarily an A-list star in her own right, but she continues to book acting gigs (https://en.wikipedia.org/wiki/Josie_Davis#Filmography) (especially in Lifetime and Hallmark movies). And I just saw on her Twitter account (https://twitter.com/JosieDavis/status/1224555946363383808) that she's going to be on Stumptown on ABC.

With Nicole, it seemed like her career more or less "peaked" with Baywatch, which came after her run on Charles in Charge ended in 1990. And in recent years, Nicole has pretty much been relegated to doing a lot of reality television (https://en.wikipedia.org/wiki/Nicole_Eggert#Filmography). And more recently, she's been in the news being the owner-operator of an ice-cream truck.

I always figured that Nicole was being set up to be the breakout star of Charles in Charge since she was the resident teen pinup/bombshell while Josie was looked at as kind of the more nerdy and plain "kid sister".

One word answer : "SPLASH!"

Honestly speaking , NICOLE EGGERT was never the same
after her nearly fatal back-flop diving accident during
the last episode of this celebrity reality competition show.

Since then, her mental state and public behavior have been
nothing short of frighteningly erratic and embarrassing.

D.J. Lethal : "Nicole, get MENTAL HELP!"

Willie Aames calls Eggert "THE TROUBLED ONE".

One word answer : "SPLASH!"

Honestly speaking , NICOLE EGGERT was never the same
after her nearly fatal back-flop diving accident during
the last episode of this celebrity reality competition show.

Since then, her mental state and public behavior have been
nothing short of frighteningly erratic and embarrassing.

D.J. Lethal : "Nicole, get MENTAL HELP!"

Willie Aames calls Eggert "THE TROUBLED ONE".

I don't know where your getting at if you're trying to be serious. I'll say that I suspect that Nicole was in the long run, likely hurt by the entire "stigma" of being on Baywatch. I believe that there's a good reason why many cast members from that show never really went land more high profile or "legitimate", mainstream acting work after being on that show. Casting directors and producers see you on this cheesy, syndicated thinly disguised "jiggle show", and it's right away hard to take you seriously as an actor.

Also, Josie has really blossomed into her looks whereas (and I know that this is going to sound really cold) Nicole after having a few kids, has really packed on a few pounds. If you've see more recent pictures of Nicole Eggert, while she's still an attractive woman, she just looks more like an above-average, suburban soccer mom. In other words, Josie Davis simply put, looks more accessible as a traditional leading lady-type.

One word answer : "SPLASH!"

NICOLE EGGERT's botched and CATASTROPHIC nearly fatal BACK FLOP DIVE
in the last episode of the celebrity reality diving competition show "SPLASH!"
resulted in self-inflicted PHYSICAL BACK INJURIES as well as obvious LONG TERM BRAIN DAMAGE
that clearly manifested itself in later years as IMAGINARY FAKE MEMORIES and TOTAL MENTAL DERANGEMENT.

After "SPLASH!" came BANKRUPTCY, ICE CREAM TRUCK DRIVING, THE ACQUITTAL OF D.J. LETHAL
and other CELEBRITY TRAINWRECK MISADVENTURES.

NICOLE EGGERT IS "THE TROUBLED ONE".

WILLIE AAMES IS "THE TAUNTING ONE".

JOSIE DAVIS IS "THE TRUTH TELLING ONE".

JENNIFER RUNYON IS "THE TANTALIZING ONE".

AND SCOTT BAIO IS "THE TRIUMPHANT ONE".

https://tvtropes.org/pmwiki/pmwiki.php/HollywoodHypeMachine/ExamplesThatDidntHoldUp

Nicole Eggert (https://nedhardy.com/2022/03/26/nicole-eggert/) started out (https://bestlifeonline.com/baywatch-nicole-eggert-now-news/) as a child actress in The '80s, before landing a role on the sitcom Charles in Charge with Scott Baio. She then moved to more adult work upon being cast (https://digitalglobaltimes.com/nicole-eggert-then-and-now/) as Summer Quinn in Season 3 of Baywatch, joining the show at the same time as Pamela Anderson (see above). Eggert departed the series following Season 4 while none of her resulting (https://tvovermind.com/whats-nicole-eggert-up-to-these-days/) acting work got the same level of popularity as Baywatch.